Residential and commercial building products include interior building products such as drywall, countertops, bathroom fixtures, kitchen cabinets, interior doors, flooring, wall panels, ceiling tiles, and building exterior products such as decking, siding, trim, fencing, windows and exterior doors. These products are made of gypsum, vinyl, acrylic, hardboard, tempered glass, annealed glass, resin composites, various laminates, veneer, low profile carpet tiles, fiberglass, ceramic, granite, plastic and plastic wood composites, and a variety of other materials. There is often a desire to offer such components in decorative fashion with various graphic designs imprinted on the materials.
Conventional printing technologies such as embossing and ink-jet printing often produce unappealing aesthetics. Other processes such as sandblasting and veneering have the drawback of high cost.
It would seem that laser engraving building products would offer an attractive means to decorate building products. However, commercial production lasers have not been used to decorate building products in a large scale production at economically attractive rates. It is believed that at least two factors explain why building products are not laser etched on a mass production scale. These factors are the relatively low scan speeds and relatively low power capabilities of commercial laser engraving systems.
With regard to scan speeds, a laser beam can be driven with linear motors or lead screw drives on x-y tables at typical laser scan speeds of typically 0.5 to 3.0 meters per second. This method is common in the laser cutting industry which uses 1,000-10,000 watt lasers to cut steel, for example. Companies such as Amada®, Trumph, Rofin®, Fanuc®, and Panasonic® provide such 1,000-10,000 watt laser systems.
The speeds of these conventional linear-motor-driven laser systems would take several total processing minutes just to etch a square foot of material. For example, a recent advertisement of a leading laser system, Vyteck L-Star, purports that it is the “world's fastest laser system for the stone, tile and glass industries”. The advertisement further purports that the “L-Star outperforms the competition with engraving speeds up to 150 ips” or 3.8 meters per second.
The inventors recognized, however, that the speeds obtained by conventional linear-motor systems would not allow economical scribe-processing of building products because it would take far too long to decorate a substrate. It is estimated that a laser of this linear-motor type would take several minutes per square foot to etch graphic patterns on building materials. For example, at this speed, it is estimated that it could take about 6 minutes to etch a complex graphic pattern on a square foot of medium density fiberboard, a common substrate for building materials. Thus, the unit manufacturing costs would be far too high to economically process such building materials on a mass scale. The slow speed of this linear motor would likely not be a practical or economical method to lase graphic patterns on wood composite decking, flooring, wood composite products or any other typical building product substrate at high volumes. It could take several minutes per square foot to lase complex wood grain patterns on a square foot of engineered wood or plastic lumber with current laser engraving technology. The inventors believe that this is why such building materials are not laser etched in high volumes.
Alternatively, galvanometer-driven mirrors (or galvo mirrors for short) can be used to control the movement of a laser beam on the surface of a material. The galvo mirrors are moved by a control signal, and that movement correspondingly causes the output beam of the laser to be moved on the material along a desired path, thereby enabling creation of a pattern. This method finds wide application in the laser engraving of a variety of materials including steel, wood and plastic, using 50-250 watt lasers.
Laser systems driven by galvo mirrors are employed on relatively small scales (generally less than 61 cm (or two feet) square field size) and at low speeds (less than 5 meters per second engraving speed) with low power (generally between 50-250 watts). These systems typically etch products such as wine glasses, small brass bushings, small wooden plaques or small granite slabs. Unlike lasers driven with linear motors, galvo mirror-driven systems lack the laser power to process relatively large parts. As with linear-motor driven lasers, the operation of galvo mirror-systems is too slow to produce building product parts economically.